Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Changes in balances of each component of accumulated other comprehensive income, net of taxes [Roll Forward]
Beginning Balance	$ 105,506	$ 102,492
Total other comprehensive income, net of tax	3,921	1,246
Ending Balance	112,983	105,506
AOCI Attributable to Parent [Member]
Changes in balances of each component of accumulated other comprehensive income, net of taxes [Roll Forward]
Beginning Balance	5,830	4,584
Total other comprehensive income, net of tax	3,921	1,246
Ending Balance	9,751	5,830
Unrealized Gains on Available-for-Sale Securities [Member]
Changes in balances of each component of accumulated other comprehensive income, net of taxes [Roll Forward]
Beginning Balance	5,830
Other comprehensive income before reclassifications	9,880
Amounts reclassified from accumulated other comprehensive income	(5,959)
Total other comprehensive income, net of tax	3,921
Ending Balance	$ 9,751	$ 5,830